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Prop ? on Genesis boat

Im currently running a 3 Blade Alloy Boat Propeller 436x4 on my genesis with the stock motor and a turnigy 180 esc. I use 2 turnigy nano-tech 6000 batteries in series and the boat seems fast. My temps are good but I want to change my prop to see if I can go faster. I'm some what new to boating but I have been in the Car, Truck and Heli hobby for the past ten years. I have a 4mm shaft on there now but I would like to convert it to 3/16 and upgrade my prop. I just dont understand what 1.4 or 1.6P means or any other measurments for that matter. I do know what diameter is but I dont know what would be to big for my set up. Can anyone suggest a prop size or explain it and also tell me how to upgrade my shaft size? Thanks

To go to 3/16" flex + stub you need to change out the strut (ose sells the upgrade strut), or mod the existing strut by boring out the strut & fitting 3/16" lead teflon bushes. Not sure how the 3/16" flex will run with no liner as the stuffing tube is stainless & not brass, maybe ok but ive only run in brass.

Yes the stock motor is 2075k. I have the 3S or 11.1V running in series (Forgot to add that). I figured the higher the pitch the farther the prop goes per rotation. I have a full size boat so I figured the pitches are relivant to each other just in smaller scale. Im just not sure how big of a diameter I should go with my set up. I really dont want to spend 20 bucks a prop just to find out its to big or worse yet burn up my esc or motor. Could anyone suggest any specifc upgrade parts to go to a 3/16 shaft or where to locate them for a good price? Thanks

Flex shaft kit and coupler and bushing for strut you can find on hear in the store or shop around some,
Now, You are running the 3s packs in series for a total of 6s ? And what ( C ) are they !
And what prop do you use ?

The batteries are 50C. I just found the strut for my boat but I havent found the Flex shaft or coupler. Im really new to boats so its taking me a while to figure this all out. I bought a 3 Blade Alloy Boat Propeller 436x4 from hobby king when I built the boat. I honestly have no idea what those numbers mean. I just shoped around on hobbyking's site and read some reviews for that prop. I haven't ran any other prop yet. I keep on reading that switching to a 3/16 shaft will give me more prop options and more reliability.

Yes im positive its in series. I am somewhat new to brushless but I do have experience with my Erevo 1/10 (1/8 depending who you talk to) and my T-rex 450. I have been mainly nitro my since I started into the hobby but know I like both. I know I've read that the most people run on my set up is 5s MAX but when I first got the boat I had the pure intentions of switching out the motor to a lepoard. I knew heat would be my issue running at 6s so I ran all new cooling lines and isolated the esc from my motor in my cooling loop. Which why I think my temps are within range. I wanted to start upgrading my drive train before i go with a new motor but I want to see how far I can push the stock one. Hopefully without completly melting it or catching my boat on fire!

She's relatively narrow, simply said: the boat will start 'rolling' around the prop on larger diameters.
(Not really but so you'll understand)

For the prop, try a 42mm maximum on that Kv. Pitch 1.4 (Octura M442?) By the way, the pitch means a factor from the diameter.
In other words 42x1.4 means 42 mm diameter, pitch 42x1.4 = 58.8
So per revolution the prop would go 58.8 mm forward in theory, IF you would have no slip.

On a similar setup I tickled 100Km/h-62mph but with 1900KV motor better quality than stock.

She's relatively narrow, simply said: the boat will start 'rolling' around the prop on larger diameters.
(Not really but so you'll understand)

For the prop, try a 42mm maximum on that Kv. Pitch 1.4 (Octura M442?) By the way, the pitch means a factor from the diameter.
In other words 42x1.4 means 42 mm diameter, pitch 42x1.4 = 58.8
So per revolution the prop would go 58.8 mm forward in theory, IF you would have no slip.

On a similar setup I tickled 100Km/h-62mph but with 1900KV motor but better quality than the stock.

Originally Posted by martin

To go to 3/16" flex + stub you need to change out the strut (ose sells the upgrade strut), or mod the existing strut by boring out the strut & fitting 3/16" lead teflon bushes. Not sure how the 3/16" flex will run with no liner as the stuffing tube is stainless & not brass, maybe ok but ive only run in brass.

I machined my strut out when I upgraded the flex to 3/16", still using original SS stuffing tube -no liner- runs fine.

She's relatively narrow, simply said: the boat will start 'rolling' around the prop on larger diameters.
(Not really but so you'll understand)

For the prop, try a 42mm maximum on that Kv. Pitch 1.4 (Octura M442?) By the way, the pitch means a factor from the diameter.
In other words 42x1.4 means 42 mm diameter, pitch 42x1.4 = 58.8
So per revolution the prop would go 58.8 mm forward in theory, IF you would have no slip.

On a similar setup I tickled 100Km/h-62mph but with 1900KV motor but better quality than the stock.

I machined my strut out when I upgraded the flex to 3/16", still using original SS stuffing tube -no liner- runs fine.

Viper1 when you machined it do you mean you drilled out a 1/4 " through the strut and then used 3/16" inner by 1/4" bushings? My concern if I were to do that is if I can get it perfectly straight. Did you use a drill press? I think it might be easier for me to just buy a strut a flex shaft and a coupler. Thank you also for explaing the prop for me. I just need to do the 3/16 conversion before I can get that prop. What 1900 motor where u using? Thanks again everyone!!!

Ok,
I did realize you new your boat was running at a saw setup. 2075kv x 22.2v = 46065 rpm
I run a neu 1515 1y 2200kv / sk 180 / 187 flex / x442 / 4s2p 30c 5000mah cells,
Also setup with a offset rudder and run pretty nice at 45mph.
Good luck with yours and get some video of it running please.

Viper1 when you machined it do you mean you drilled out a 1/4 " through the strut and then used 3/16" inner by 1/4" bushings? My concern if I were to do that is if I can get it perfectly straight. Did you use a drill press? I think it might be easier for me to just buy a strut a flex shaft and a coupler. Thank you also for explaing the prop for me. I just need to do the 3/16 conversion before I can get that prop. What 1900 motor where u using? Thanks again everyone!!!

Not 'through' as the orig tube is smaller then 1/4" O.D., it's 6mm so only the part for the bushes are drilled. Yes I used a lathe. Buying is always easier
I used this motor .
It's a ripper, try it and I promise you won't regret it.

Not 'through' as the orig tube is smaller then 1/4" O.D., it's 6mm so only the part for the bushes are drilled. Yes I used a lathe. Buying is always easier
I used this motor .
It's a ripper, try it and I promise you won't regret it.

Did you machine the strut slightly under 1/4" so the bushes were a push in fit or use loctite to hold the bushes.

I've just done the 3/16 upgrade on my genesis.
If you swap the strut out you will need to make sure the one you get fits the stuffing tube or you will need to replace it also. I got a 3/16th octura strut with skeg from OSE which would not fit the original stuffing tube and was to suit an odd size of brass tube I couldn't get locally. I recommend you make sure you get the right one with your order from here or just get the upgrade strut that fits straight up. save yourself a bunch of work.
3/16 .187 is defo the way to go. dont waste your time with 3/16 .150 and buy assembled
I ran mine with the stock motor on 5s with a TFL 440 prop, it did 80km/h but got a bit hot. (60degC)